Influence of neutron and gamma radiation on YBCO and GdBCO/Ag superconducting bulks

Superconducting single-domain YBCO and GdBCO/Ag bulks were tested for space and nuclear applications by an exposition to increasing doses of gamma and neutron radiation in the LVR-15 research reactor. Maximum doses were 3.85E+04 Gy from neutron and 7.00E+05 Gy from gamma radiation, which is much larger dose then can be received in any spacecraft during the standard space mission. Levitation force and trapped field of the irradiated samples as well as non-irradiated samples were measured after each irradiation step. The appearance and phase composition of the surface and interior of all samples were examined by XRD and SEM after the final irradiation. The surface of the ceramics was damaged in respect of visual (SEM) appearance and the phase composition (XRD). Nevertheless, the interior is similar to the standard non-irradiated samples. More importantly, the trapped field and the levitation force remained also comparable for irradiated and non-irradiated samples even after the highest dosage experiment. From the results it is apparent, that the superconducting levitation discs of similar composition, shape and size can be securely used for space applications as well as for nuclear applications when the dose of irradiation is comparable to the undertaken experiments. The attention has to be paid to the very small parts, where the surface damage may cause some problems in performance.